Identify (X), (Y) and (Z) in the given reaction.
`X +Y overset(Z) to underset("3-Hydroxybutanal")(CH_(3)-overset(OH)overset(|)(CH)-CH_(2))-CHO`

Options

A. `{:(X,Y,Z),(HCHO,CH_(3)CHO,KOH):}`
B. `{:(X,Y,Z),(CH_(3)CHO,CH_(3)CHO,NaOH):}`
C. `{:(X,Y,Z),(CH_(3)CH_(2)OH,HCHO,H_(2)SO_(4)):}`
D. `{:(X,Y,Z),(CH_(3)CH_(2)CHO,HCHO,"Dry ether"):}`

Answer

To solve the problem, we need to identify the compounds (X), (Y), and (Z) in the reaction that leads to the formation of 3-Hydroxybutanal (CH₃-CHOH-CH₂-CHO).

### Step-by-Step Solution:

1. **Understanding the Reaction**:
The reaction is an aldol reaction, which typically involves the reaction of two aldehydes or ketones in the presence of a base to form a β-hydroxy aldehyde or ketone.

2. **Identifying Z**:
In aldol reactions, a base is required to deprotonate the alpha hydrogen of the carbonyl compound. The problem states that Z is the reagent used to facilitate this reaction. The common base used in aldol reactions is sodium hydroxide (NaOH).
- **Thus, Z = NaOH**.

3. **Identifying X and Y**:
The product is 3-Hydroxybutanal, which has four carbon atoms. For the aldol reaction to yield this product, we need two carbonyl compounds (X and Y) that can combine to form a four-carbon product.
- The simplest aldehyde that can be used in this reaction is acetaldehyde (CH₃CHO), which has two carbon atoms.

4. **Combining X and Y**:
Since we need a total of four carbons in the reactants (X and Y), we can use two molecules of acetaldehyde:
- **X = CH₃CHO (acetaldehyde)**
- **Y = CH₃CHO (acetaldehyde)**

5. **Final Identification**:
Therefore, we conclude:
- **X = CH₃CHO (acetaldehyde)**
- **Y = CH₃CHO (acetaldehyde)**
- **Z = NaOH**

### Summary:
- **X = CH₃CHO (acetaldehyde)**
- **Y = CH₃CHO (acetaldehyde)**
- **Z = NaOH**